1. Field of the Invention
The present invention relates to an imaging apparatus and, more particularly, to an imaging apparatus provided with two image pickup means.
2. Description of the Related Art
As one example of this kind of imaging apparatus, an optical binocular telescope has heretofore been known which can provide an observer a subject image having a visually preferable stereoscopic effect. The optical binocular telescope is arranged, for example, as shown in FIG. 5. The arrangement shown in FIG. 5 includes objective lens systems 41a and 42a, rectangular prisms 42a, 42b, 43a and 43b for folding their associated optical paths and for converting their respective inverted images into erecting images, eyepiece lens systems 44a, 44b, 45a, 45b, 46a and 46b, and optical paths 47a and 47b of the respective optical systems.
As shown in FIG. 5, the optical paths of subject lights which pass through the respective objective lens systems 41a and 41b are folded by the rectangular prisms 42a and 43a and the rectangular prisms 42b and 43b. Accordingly, it is possible to convert the respective inverted images into erecting images, and it is also possible to reduce the overall length of a lens barrel (not shown) without reducing the lengths of the respective optical paths. The subject lights whose optical paths have been folded by the rectangular prisms 43a and 43b respectively reach the observer's eyes through the eyepiece lens systems 44a, 45a, 46a and 44b, 45b, 46b.
However, an optical binocular telescope, such as the above-described related-art example, has a number of problems. For example, since it is desirable that a subject image be observed with the naked eye as an erecting image, it is necessary to insert an element for converting an inverted image into an erecting image, for example, rectangular prisms such as the above-described ones, between each objective lens and its associated eyepiece lens. Also, if the size of the binocular telescope is to be reduced, it is necessary to reduce its lens barrel by inserting the rectangular prisms or the like into each optical path and folding the optical path.
Further, it is difficult for the observer to confirm various information as to photographing states, such as the magnification of the binocular telescope, while viewing a subject image.